Poly(thymine)-Templated Copper Nanoparticles as a
Fluorescent Indicator for
Hydrogen Peroxide and Oxidase-Based Biosensing
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Abstract
Biomineralized fluorescent metal
nanoparticles have attracted considerable
interest in many fields by virtue of their excellent properties in
synthesis and application. Poly(thymine)-templated fluorescent copper
nanoparticles (T-CuNPs) as a promising nanomaterial has been exploited
by us recently and displays great potential for signal transducing
in biochemical analysis. However, the application of T-CuNPs is rare
and still at an early stage. Here, a new fluorescent analytical strategy
has been developed for H<sub>2</sub>O<sub>2</sub> and oxidase-based
biosensing by exploiting T-CuNPs as an effective signal indicator.
The mechanism is mainly based on the poly(thymine) length-dependent
formation of T-CuNPs and the probe’s oxidative cleavage. In this assay, the probe
T40 can effectively template the formation of T-CuNPs by a fast <i>in situ</i> manner in the absence of H<sub>2</sub>O<sub>2</sub>, with high fluorescent signal, while the probe is cleaved into short-oligonucleotide
fragments by hydroxyl radical (·OH) which is formed from the
Fenton reaction in the presence of H<sub>2</sub>O<sub>2</sub>, leading
to the decline of fluorescence intensity. By taking advantage of H<sub>2</sub>O<sub>2</sub> as a mediator, this strategy is further exploited
for oxidase-based biosensing. As the proof-of-concept, glucose in
human serum has been chosen as the model system and has been detected,
and its practical applicability has been investigated by assay of
real clinical blood samples. Results demonstrate that the proposed
strategy has not only good detection capability but also eminent detection
performance, such as simplicity and low-cost, holding great potential
for constructing effective sensors for biochemical and clinical applications